diff --git a/src/LogBackend.cxx b/src/LogBackend.cxx
index 67c1e4caa..ec4bf0faa 100644
--- a/src/LogBackend.cxx
+++ b/src/LogBackend.cxx
@@ -81,10 +81,10 @@ EnableLogTimestamp() noexcept
 static std::string_view
 log_date() noexcept
 {
-	static constexpr size_t LOG_DATE_BUF_SIZE = std::char_traits<char>::length("2025-01-22 15:43:14 : ") + 1;
+	static constexpr size_t LOG_DATE_BUF_SIZE = std::char_traits<char>::length("2025-01-22T15:43:14 ") + 1;
 	static char buf[LOG_DATE_BUF_SIZE];
 	time_t t = time(nullptr);
-	return FmtUnsafeSV(buf, "{:%F %T} : "sv, fmt::localtime(t));
+	return FmtUnsafeSV(buf, "{:%FT%T} "sv, fmt::localtime(t));
 }
 
 #ifdef HAVE_SYSLOG